NAPAC2016 - List of Authors (Harris, J.R.)

Paper	Title	Page
WEPOB25	Analytical Modeling of Electron Back-Bombardment Induced Current Increase in Un-Gated Thermionic Cathode Rf Guns	953
	J.P. Edelen Fermilab, Batavia, Illinois, USA J.R. Harris Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, USA J.W. Lewellen LANL, Los Alamos, New Mexico, USA Y. Sun ANL, Argonne, Illinois, USA
	In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, field-enhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB25
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WEPOB26	Observation of Repetition-Rate Dependent Emission From an Un-Gated Thermionic Cathode Rf Gun	956
	J.P. Edelen Fermilab, Batavia, Illinois, USA J.R. Harris Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, USA J.W. Lewellen LANL, Los Alamos, New Mexico, USA Y. Sun ANL, Argonne, Illinois, USA
	Recent work at Fermilab in collaboration with the Advanced Photon Source and members of other national labs, designed an experiment to study the relationship between the RF repetition rate and the average current per RF pulse. While existing models anticipate a direct relationship between these two parameters we observed an inverse relationship. We believe this is a result of damage to the barium coating on the cathode surface caused by a change in back-bombardment power that is unaccounted for in the existing theories. These observations shed new light on the challenges and fundamental limitations associated with scaling an un-gated thermionic cathode RF gun to high average current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB26
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Analytical Modeling of Electron Back-Bombardment Induced Current Increase in Un-Gated Thermionic Cathode Rf Guns

953

J.P. Edelen
Fermilab, Batavia, Illinois, USA
J.R. Harris
Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, USA
J.W. Lewellen
LANL, Los Alamos, New Mexico, USA
Y. Sun
ANL, Argonne, Illinois, USA

In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, field-enhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB25

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOB26

Observation of Repetition-Rate Dependent Emission From an Un-Gated Thermionic Cathode Rf Gun

956

J.P. Edelen
Fermilab, Batavia, Illinois, USA
J.R. Harris
Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, USA
J.W. Lewellen
LANL, Los Alamos, New Mexico, USA
Y. Sun
ANL, Argonne, Illinois, USA

Recent work at Fermilab in collaboration with the Advanced Photon Source and members of other national labs, designed an experiment to study the relationship between the RF repetition rate and the average current per RF pulse. While existing models anticipate a direct relationship between these two parameters we observed an inverse relationship. We believe this is a result of damage to the barium coating on the cathode surface caused by a change in back-bombardment power that is unaccounted for in the existing theories. These observations shed new light on the challenges and fundamental limitations associated with scaling an un-gated thermionic cathode RF gun to high average current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB26

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)